DESIGN: Brisbane City Council has unveiled the preferred design for the delayed Kingsford Smith Drive upgrade. See the design in full below. Source: Supplied

LORD mayor Graham Quirk has used the announcement of a possible deal to off-load tolling rights for the Go Between bridge and Legacy Way to unveil the preferred design for the delayed next stage of the Kingsford Smith Drive upgrade.

While no timeframe has been set on the infrastructure project, which has regularly been identified as council's "next priority", Cr Quirk said the about $650 million in savings potentially achieved through the bridge and tunnel deal with QIC and Queensland Motorways could bring forward the start date of the much-needed inner-northside upgrade.

Stage two of the Kingsford Smith Drive project involves the widening of a stretch from the Gateway Bridge to Racecourse Road from four to six lanes and is estimated to cost $192 million.

Stage three comes with an estimated $600 million price tag and involves widening the remaining stretch of road from four to six lanes, via a retaining wall to be built out on to the Brisbane River.

The upgrade would also involve a separated cantilevered section for pedestrians and cyclists, which would also extend out on to the river.

Any deal with QIC and Queensland Motorways could see the start date for the project – which presently sits at "post-2017'' – brought forward.

Earlier, Brisbane City Council moved to shield ratepayers from a hip-pocket hit if the city's next tunnel project fails to take off, but the Opposition has raised doubts about the deal.

The yet-to-be-finalised deal would see the state-backed Queensland Investment Corporation and Queensland Motorways taking over tolling rights for the tunnel and the Go Between Bridge.

Lord Mayor Graham Quirk will today confirm negotiations are under way after the council was approached to hand over operational control of the $1.5 billion tunnel and $308 million bridge, most likely under a 50-year lease.

The deal would leave BCC at least partially shielded from hundreds of millions of dollars in losses, which the tunnel alone is expected to generate during its initial years of operation.

But the council's Labor opposition Leader Milton Dick said the proposed deal essentially amounted to QIC and Queensland Motorways bailing council out of the "risky" Legacy Way project.

He also raised concerns about any residual debt left with council after the deal and added the move was proof the financial case for the tunnel had never stacked up.

"I'm worried that in this deal, Council will forfeit future tolling revenue but will still hold hundreds of millions of Legacy Way debt and I call on the Lord Mayor to release details of his negotiations with QIC so ratepayers can know what their Council have signed them up for."

The new operators would also take on the costs such as road maintenance and repairs, reducing council's expenses.

Council's $1 billion investment in Legacy Way as well as ratepayers' ongoing financial exposure to the project, have previously raised concerns particularly in light of the underwhelming performances of the Clem7 and Airport Link tunnels.

Cr Quirk denied the possible deal was a relief and said he remained "very positive about Legacy Way".

He said the deal could save ratepayers $650 million in costs during the next seven years and added that money, and additional revenue generated, could fund other infrastructure projects, such as upgrades to Wynnum Rd and Kingsford Smith Drive.

"QIC are a funds manager so they see a long-term revenue stream opportunity," he said.

"For us it's about getting cash upfront. It's about allowing us to get on to do those other infrastructure jobs in the city that need doing."

Cr Quirk said the handover of Legacy Way would not occur until the early-2015 completion of the construction project.

He added it would be up to the new operators to set tolls for both assets, within a State Government cap.

Queensland Motorways CEO Brendan Bourke confirmed both his organisation - which already operates the Gateway and Logan motorways - and its owner QIC aimed to finalise a deal by June.

Cr Dick said there was a "silver lining" in the Lord Mayor's commitment that money raised or save by council would be put towards the delayed upgrade of Kingsford Smith Drive.

It remains unclear at this stage how much of the tunnel debt QIC and Queensland Motorways would take on as part of any deal.

Based on current council forecasts Legacy Way is not expected to be economically viable until the 2026-27 financial year, while the Go Between Bridge will not be viable until 2030-31.

Under the current proposal council would receive upfront payments for each asset with further income linked to asset performance over time.

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